PPE
Chris Webb outlines Avon’s courses for successful protection
has evolved with the use of chemical-resistant rubbers as the key material for its construction. Rubber is used because of its fl exibility and durability and also because it is able to create an airtight seal around the face. Today’s modern mask is also designed for
greater comfort with built in drinking facilities and two way radio communications. And technological advances like voice projection and head up displays are now being worked on. Visual protection under all extremes is also essential with the use of toughened, scratch resistant polycarbonate or polyurethane visors, often with tinted outserts to protect the wearer against UV or laser beams.
The fi lter is the key component to the
effi cacy of any gas mask, as it always has been. Original masks from both World Wars used materials ranging from gauze, asbestos fi bres and paper fi lters to remove particulate materials. The challenge is to create a subsequent layer of materials – charcoal being particularly eff ective - to fi lter out the chemical compounds that constitute toxic gases and vapours.
Today’s demands Today, masks must cope with all extremes of CBRN. To guard against a biological threat, a very fi ne particulate fi lter is needed. An
anthrax spore, for example, might have a minimum size of one micron. So Avon’s particulate fi lters remove particle sizes as small as 0.003 microns – nano-particle size! Wearer comfort is a key factor in modern mask design. The fi rst thing a wearer notices when donning a mask is that normal breathing is slightly restricted because the wearer has to work hard to pull air through the fi lter materials which are removing the noxious particulates and gases in the atmosphere. For a normal, fi t military, police or emergency operator this poses no problem. However, when it comes to activities that demand extreme exertion on the battlefi eld
CHEMICAL, BIOLOGICAL & NUCLEAR WARFARE | 2012/02 | 35
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